At present, intelligent display terminals are increasingly pursuing a high-resolution and high-brightness liquid crystal display module, which undoubtedly needs to use a higher-brightness backlight unit (BLU). Based on a current LED brightness level, a design of the high-brightness backlight unit needs to use more LEDs or adopt a double crystal LED to implement brightness improvement. As the number of LED chips used in a single backlight unit increases, thermal power consumption also increases. How to resolve a problem of LED heat is a subject worthy of study. A heat-radiating structure of the existing backlight module is to add a graphite heat-radiating sheet under a reflecting sheet or a metal back plate which is at the backlight bottom, and a defect thereof is: a thickness of the module increases.